#include <stdio.h>
#include <math.h>
int main()
{
    long i;
    int j;
    printf("please input number:");
    scanf("%ld", &i);
    for (j = 999; j >= 100; j--)
    {
        if (i % j == 0)
        {
            printf(" the max factor with 3 digits in %ld is:%d \n", i, j);
            break;
        }
    }
    return 0;
}